The present disclosure relates to a developer transporting mechanism that is used in an image forming apparatus such as a copier, a printer, a facsimile machine, or a multifunctional peripheral of these devices. More particularly the disclosure relates to a mechanism that opens and closes a developer discharge port formed in a path through which a developer is transported.
Using an image forming apparatus, a latent image formed on an image supporting body including a photosensitive body and the like is developed by a developing device so that the latent image is made visible as a toner image. An example of such a developing device is a developing device that employs a two-component developing method in which a two-component developer is used. This type of developing device has a developer vessel in which the two-component developer, which includes magnetic carriers and toner, is stored. In addition, the developing device has a developing roller through which the developer is supplied to the image supporting body and also includes a stir-transport member that transports the developer from the developer vessel to the developing roller while agitating the developer.
Using a developing device employing a two-component developing method, toner is consumed in the developing operation, but carriers may remain that are not consumed. Accordingly, as carriers are more often stirred in the developer vessel together with toner, the carriers may be more deteriorated. As a result, the charging performance of the carriers to toner may be gradually reduced.
To prevent the deterioration of the charging performance of the carriers, a developing device having a developer discharge portion from which an extra amount of developer is discharged is disclosed.
A developing device having a developer discharge portion as described above, is transported in a state in which the developing device is attached in an image forming apparatus. Alternatively, a developing device having a developer discharge port is packed separately from an image forming apparatus and transported. The developer in the developer vessel may leak and may fly out from the developer discharge port due to vibration or shock during transport, so the interior of the image forming apparatus may be contaminated.
Accordingly, a shutter is used that covers the developer discharge port before the developing device is transported. When the image forming apparatus is set up, the shutter is opened and then the developing device, with open shutter, is attached to the image forming apparatus. Alternatively, after the developing device has been attached to the image forming apparatus, the shutter is opened.
When the image forming apparatus is transported in a state in which the developing device, the developer discharge port of which is opened and closed with the shutter, is attached to the image forming apparatus, the developer may leak from a clearance between the outer circumferential surface of the developer discharge portion and the inner surface of the shutter due to vibration or shock during transportation. To prevent the developer from leaking, a sealing member is provided between the outer circumferential surface of the developer discharge portion and the inner surface of the shutter. If, however, the sliding load between the shutter and the sealing member becomes large, the shutter may fail, in which case the developer discharge port may not be completely closed and thereby the developer may leak from the developer discharge port. If a sliding area between the sealing member and the shutter is reduced, the sliding load is reduced, but the sealing effect may be reduced.
The sealing member is located, for example, between the shutter and a pipe-like path through which waste toner, which has been removed from the image supporting body, is transported. As the sealing member located between the shutter and the pipe-like path is elongated in the sliding direction of the shutter, the sealing effect is improved. However, a problem arises in that the sliding resistance to the shutter is increased and the shutter is thereby not easily opened or closed. Conversely, if the length of the sealing member in the sliding direction of the shutter is shortened, the shutter can be opened and closed smoothly, but another problem arises in that a superior sealing effect cannot be achieved.